1. Field of the Invention
The present disclosure relates to systems for tracking movable objects, including but not limited to shopping carts.
2. Description of the Related Art
A variety of commercially available cart containment systems exist for deterring the theft of shopping carts. Typically, these systems include a wire that is embedded in the pavement of a store parking lot to define an outer boundary of area in which shopping cart use is permitted. When a shopping cart is pushed over this wire, a sensor in or near one of the wheels detects an electromagnetic signal generated via the wire, causing the wheel to lock. To unlock the wheel, an attendant typically uses a handheld remote control to send an unlock signal to the wheel.
While existing cart containment systems are useful for deterring shopping cart theft, they are generally not capable of detecting other types of shopping cart misuse. As one example, existing systems are unable to detect that a shopping cart is being used to steal groceries or other merchandise. While merchandise theft can often be detected using an Electronic Article Surveillance (EAS) system, the cost and burden of attaching EAS tags to merchandise items is often impractical. As another example of misuse, merchants that use power-assisted cart retrieval units sometimes use these machines to retrieve too many carts at a time, or to push a cart having a locked or improperly oriented wheel.
This background section is not intended to suggest that the present invention is limited to shopping carts, or that the invention requires detection of the particular types of misuse described above.